<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <script>
        var socket;
        // 判断当前浏览器是否支持websocket
        if (window.WebSocket){
            // go on
            socket = new WebSocket("ws://localhost:7000/hello");
            // 相当于 channelRead0，ev 收到服务器回送的消息
            socket.onmessage = function (ev) {
                var rt = document.getElementById("responseText");
                rt.value = rt.value + "\n" + ev.data;
            }

            // 相当于连接开启（感知到连接开启）
            socket.onopen = function (ev) {
                var rt = document.getElementById("responseText");
                rt.value = "连接开启了。。。";
            }

            // 相当于连接开启（感知到连接关闭）
            socket.onclose = function (ev) {
                var rt = document.getElementById("responseText");
                rt.value = rt.value + "\n" + "连接关闭了~~~";
            }

            // 发送消息到服务器
            function send(message) {
                if(!window.socket){
                    return;
                }
                if (socket.readyState == WebSocket.OPEN){
                    // 通过socket 发送消息
                    socket.send(message)
                } else {
                    alert("连接没有开启")
                }
            }

        }else {
            alert("当前浏览器不支持 websocket")
        }

    </script>

    <form onsubmit="return false">
        <textarea name="message" style="height: 300px;width: 300px"></textarea>
        <input type="button" value="发送消息" onclick="send(this.form.message.value)">
        <textarea id="responseText" style="height: 300px; width: 300px"></textarea>
        <button type="button" value="清空内容" onclick="document.getElementById('responseText').value=''"></button>
    </form>

</body>
</html>